Twelfth seed Ivanovic was the favourite but it was Canadian teenager Bouchard who upset the odds to progress.
Read how it all unfolded in our game-by-game updates below.
1.21pmRighty ho, after Azarenka's last-minute withdrawal it's now Ana Ivanovic on Centre Court against Eugenie Bouchard. Warm-ups have just finished and the players are ready to start. Canadian teenager Bouchard to serve first.
1.24pmFirst point to Ivanovic as Bouchard hits long but she makes up for it with a big serve that Ivanovic can't get back in play.
1.26pmIvanovic has two break points at 15-40 but they're both saved by Bouchard.
1.28pmLovely crosscourt backhand on the run from Bouchard earns the chance to hold serve in the opening game.
Bouchard 1-0* IvanovicA big forehand to the corner can't be returned by Ivanovic and that's the first game to the Canadian. An encouraging hold.
1.30pmIvanovic begins her first service game with a booming ace out wide.
1.32pmAt 30-30, Bouchard guesses right from Ivanovic's forehand and should open up break point but fires long with a forehand.
1.33pmWell played! Bouchard has a break point as she stays in the point with Ivanovic at the net before passing the Serbian.
Bouchard *2-0 IvanovicBREAK! Ivanovic with a tame double fault and the teenager has an early advantage on Centre.
1.36pmIvanovic with a couple of booming returns early on in the third game and she's 15-30 up as she looks to break back straight away.
Bouchard 3-0* IvanovicBouchard reels off three points in a row in rapid fashion and what a start this has been for the 19-year-old.
1.38pmWHO? Some of you may be wondering who young Miss Bouchard is. She is a Canadian 19-year-old playing in her first senior Wimbledon. She knows her way around the grass here though as she won the junior title 12 months ago. She is currently ranked at a career-high 66 in the world and is Canada's top woman.
1.39pmThe sun breaks through the clouds at Wimbledon. We're expected to have a third dry day in a row at SW19. Yippee!
Bouchard 4-1* IvanovicThis is really impressive from Bouchard. She's not faltering at all at the moment despite her huge lack of experience compared to her opponent.
1.47pmIvanovic looks up to her box for support after a tame drop shot doesn't make it over the net. She has to pick it up here.
Bouchard *4-2 IvanovicNo real threat from Bouchard on the Ivanovic serve since that initial break. The Canadian doesn't need to break though, it's Ivanovic who needs to step it up when receiving.
Bouchard 5-2* IvanovicIvanovic tries her best to attack the Bouchard serve but the Canadian's defence is just too good and she moves within one game of the first set.
1.52pmA comedy moment for the crowd on Centre as a ball is mishit high into the air and then dropped by double Olympic gold medallist Mo Farah in the Royal Box.
Bouchard *5-3 IvanovicComfortable hold to love for Ivanovic and it's now over to Bouchard to hold her nerve and serve out the set.
Bouchard 6-3 0-0* IvanovicSET! No jitters whatsoever from the teenager as she holds to love to take the opener in just over half an hour.
1.57pmMenacing start to the second from Bouchard and she has three break points as Ivanovic fires wide with a backhand up-the-line.
Bouchard 6-3 *1-0 IvanovicBREAK! As in the first set, Bouchard has broken at the first time of asking. It's poor from Ivanovic as she frames an easy backhand into the net.
2pmIvanovic challenges a late call on the baseline but HawkEye shows that it was indeed out.
Bouchard 6-3 2-0* IvanovicBouchard must be wondering if it's always this easy against a top seed on Centre Court at Wimbledon! Another comfortable hold to 15 for the Canadian who hasn't offered a single break point since the opening game of the match.
2.04pmAt 40-0 it looks as if Ivanovic will hold easily but Bouchard prolongs the game a little longer with a firm low pass that the Serb can't loop over the net.
Bouchard 6-3 *2-1 IvanovicThe 12th seed does hold on the next point though, kneeling low to push a forehand up the line that Bouchard can then only drag wide with her backhand.
2.06pmA fortunate start to the next game for Ivanovic as she looks to break back. Bouchard tries to lob the Serb but doesn't get enough on it and she has an easy smash. However, Ivanovic lashes the high ball into the tape and luckily for her it plops over the net.
2.08pmBouchard hits long with a backhand and Ivanovic has two break-back points...
Bouchard 6-3 2-2* IvanovicBREAK BACK! The 12th seed is back on level terms and now we're really going to see what Bouchard is made of.
2.10pmNow it's Bouchard who has a share of the luck with a net cord. She's looking to break again at 0-30 up.
2.11pmAnd now 0-40 as Ivanovic's forehand barely makes it halfway up the net.
Bouchard 6-3 *3-2 IvanovicBREAK! Brilliant stuff from the teenager as she blocks a service crosscourt before finding the far corner with a forehand winner.
2.14pmThis is a shadow of the Ana Ivanovic who won the French Open in 2008 and was once world number one. Her movement is sluggish and she's being completely outshone by her younger counterpart.
2.15pmJust as I say that, Bouchard double faults twice in a row when 40-15 up. Now deuce.
2.16pmA clench of the fist from Ivanovic as Bouchard nets with a forehand to win the game. Can the Serb make it three breaks of serve in a row?
Bouchard 6-3 *5-2 IvanovicDOUBLE BREAK! Deary me, what a limp performance this is from Ivanovic. She's broken again and now Bouchard will serve for the match and a place in round three of Wimbledon.
2.23pmYou might expect Ivanovic to give up but she now has two points to get back one of the breaks.
Bouchard 6-3 5-3* IvanovicONE BREAK BACK! The first is wasted as Ivanovic hits long but she converts the second in style, tracking down Bouchard's surprise drop shot and then finding the line with a backhand.
2.26pmDouble fault from Ivanovic at 15-30 and Bouchard has TWO MATCH POINTS.